Study of p53 and bcl-2 Oncoproteins in Ulcerative Colitis with Dysplasia

Dysplasia in ulcerative colitis has been graded on haematoxylin and eosin stain using Riddle's criteria. This system was formed to nullify the inter-observer variation. Few cases of early dysplasia were missed when purely screened on morphology. This study was carried out to detect early dysplasia using p53 and bcl-2 oncoproteins.

A retrospective study was carried out on paraffin blocks of 100 histologically diagnosed cases of ulcerative colitis at a large service hospital. Haematoxylin and Eosin stained (H &E) slides of these cases were re-examined as per standard techniques.

On correlating histological grades with p53 immunoscore it was found that 90.76% of cases graded as negative for dysplasia on H & E, got an immunoscore of 0 and other 9.24% cases which were graded as negative for dysplasia got a score 1+. This shows that the immunohistochemistry was able to pick up 6 cases, which were missed by routine histology. Nine out of 11 cases in which the pathologists could not rule out a dysplasia and graded them as indefinite (probably negative for dysplasia) got a score of 0. In these cases possibly the histological features may be construed as an acute inflammation or repair induced dysplasia which were suspicious for neoplastic dysplasia on routine histology sections. On analyzing our findings on bcl-2 immunohistochemistry it was seen that there was no significant concordance (p>0.05) of immunoscore with the grades of dysplasia estimated morphologically.

Our study recommends that p53 should be used as regular immunohistochemical marker while grading the dysplasia of ulcerative colitis, especially in indefinite cases as it brings objectivity in grading. Our study also came to a conclusion that use of bcl-2 for grading dysplasia of ulcerative colitis is not of any significant help.